Regulation and Homeostasis in the

Human Body:

Overview

How do Humans and other complex mammals maintain homeostasis? They must carry out all needed life functions in a coordinated way.

What does our species need to accomplish?

Growth Repair of injuries

Get energy Get building materials

Get rid of waste

Keep away disease

Respond to changing environment

Reproduce

Eleven Body Systems work together to maintain homeostasis and carry out these tasks:

1. Nervous System 2. Endocrine System

3. Lymphatic System 4. Circulatory System

5. Respiratory System 6. Digestive System

7. Excretory System 8. Skeletal System

9. Muscular System 10. Integumentary System

11. Reproductive System

1. Nervous System:

Structures: Brain, Spinal Cord, Peripheral Nerves, Neurons (Cells of nervous system)

Functions: Coordinates the body’s response to changes to internal and external environment

2. Endocrine System – Hormone System

Structures: Glands - Hypothalmus, pituitary, thyroid, parathyroids, adrenals, pancreas, ovaries (in females), testes (in males)

Functions: Produce Hormones. Controls growth, development, metabolism, and reproduction

3. Lymphatic System – Immune System

Structures: White blood cells, thymus, spleen, lymph nodes, lymph vessels

Function: Helps protect the body from disease; collects fluid lost from blood vessels; returns the fluid to the circulatory system

4. Circulatory System

Structures: Heart, Blood vessels, blood

Functions: Brings oxygen, nutrients, and hormones to cells; fights infection; regulates body temperature

5. Respiratory System

Structures: Nose, pharynx, larynx, trachea, bronchi, bronchioles, lungs

Functions: Provides oxygen needed for cellular respiration and removes carbon dioxide from body

6. Digestive System

Structures: Mouth, pharynx, larynx, esophagus, stomach, liver, pancreas, small and large intestines,

Function: Breaks down foods into simple molecules that can be used by the body for respiration and building cells

7. Excretory System

Structures: Skin, lungs, kidneys (nephrons), ureters, urinary bladder, urethra

Functions: Removes waste products of metabolism from the body

8. Skeletal System

Structures: Bones, cartilage, ligaments, tendons

Functions: Supports the body; protects internal organs; allows movement; stores mineral reserves; provides a site for blood formation

9. Muscular System

Structures: Skeletal muscle, smooth muscle, cardiac muscle

Function: Works with skeletal system to produce voluntary movement; helps circulate blood and move food through the digestive system

10. Integumentary System (Skin)

Structures: Skin, Hair, Nails, Sweat and Oil Glands

Functions: Serves as a barrier against infection and injury; Helps to regulate temperature; Protects against UV light

Structures:

Female- Uterus, Fallopian tubes, ovary, cervical canal, cervix, vagina

Male – Penis, Vas Deferens, Prostate, Epididymis, Testes, Scrotal Sac, Seminal Vesicle

Function: Produces reproductive cells; in females nurtures and protects developing embryo

11. Reproductive System

Support and Motion

Functions of the SKELETAL AND MUSCULAR SYSTEM

How does the human body move from place to place and have the ability to run, blink or build things?

These things are all made possible by the skeletal and muscular systems.

Skull

Sternum

Ribs

Vertebral column

Metatarsals

Metacarpals

Phalanges

ClavicleScapula

Humerus

RadiusPelvisUlnaCarpals

Femur

Patella

FibulaTibiaTarsals

Phalanges

A. Skeletal System

There are 206 bones in the adult human body. These bones provide a system of supports and levers on which muscles can produce movement

Figure 36-3 The Structure of BoneBones are a solid network of living cells and protein fibers that are surrounded by calcium deposits. Bones contain blood vessels and cavities containing marrow. Red marrow produces red blood cells, white blood cells and platelets

Bone Marrow

Ball-and-Socket Joint

Hinge Joint

Pivot Joint

Saddle Joint

Clavicle

Figure 36-4 Freely Movable Joints and Their Movements

Section 36-1

Joints are places where one bone attaches to another. Each type of joint is designed to allow movement without damaging the other bones. Joints in the skull allow no movement, joints in the spine allow a small amount of movement and those shown below allow movement in one or more directions.

Knee

Elbow

Muscle

Tendon

Femur

PatellaBursaLigament

Cartilage

Fat

Fibula

Tibia

Knee JointSection 36-1

Ligaments are a tough connective tissue that attach bones to bones

Tendons are connective tissue which attach bones and muscles to allow bones to move

B. The Muscular System

More than 40% of the average human is muscle. Muscles are involved in both voluntary actions and involuntary actions. Three types of muscles cells are:

•Skeletal – Attached to bones for voluntary actions and controlled by the central nervous system

•Smooth – Found in the digestive tract and the blood vessels to move food and blood. Control involuntary actions (you do not decide for them to work)

•Cardiac – Heart muscle cells are involuntary.

Figure 36-7 Skeletal Muscle Structure

Section 36-2Skeletal muscles are made up of clusters of filaments of proteins known as actin and myosin which control muscle contraction and relaxation

Nervous system cells known as motor neurons are attached to skeletal muscle cells to control the voluntary movement.

Threadlike Nerve or neuron

Axon or junction

Figure 36-8 Muscle Contraction

During Muscle contraction Actin filaments slide over myosin filaments shrinking the muscle

Energy for muscle contraction is supplied by ATP

Movement

MovementBiceps

(relaxed)

Triceps (contracted)

Biceps (contracted)

Triceps (relaxed)

Figure 36-11 Opposing Muscle Pairs

Section 36-2Skeletal muscles work in opposing pairs. When one muscle contracts, the other relaxes.

How does the human body take in required nutrients and get rid of wastes?

The Digestive and Excretory Systems are responsible for bringing in food and getting rid of the leftovers.

Nutrition and Waste Removal

Food supplies the raw materials for building molecules your body needs, such as:

• enzymes

• Lipids in cell membranes

• DNA

Food contains 45 substances your body needs but cannot manufacture.

Overview of Nutrients

The nutrients your body needs are water, carbohydrates, fats, proteins, vitamins and minerals.

WATER – Most of the bodies reactions take place in water. Humans need an average of 1 liter of water a day. Dehydration causes many problems throughout the body.

CARBOHYDRATES – Sugars and starches are used by the body to provide the simple sugars needed for Respiration (energy)

FATS- Deposits of fats protect body organs, insulate the body and store energy, make up cell membranes and coat the nervous system cells

PROTEINS – Supply the raw materials for growth and repair in the form of enzymes

VITAMINS – Organic molecules that work with enzymes to control body processes.

MINERALS – Inorganic nutrients that are needed in small amounts. Calcium is needed to build bones, Iron is needed for red blood cells.

Fats

Sugars

 Food Guide Pyramid

A Balanced Diet

C. The Digestive System

Pharynx

Esophagus

Liver

Gallbladder

Rectum

Mouth

Salivary Glands

StomachPancreas behind stomach

Large Intestine

Small Intestine

The Process of Digestion: The path of food

Each organ of the digestive system helps convert foods into simpler molecules that can be absorbed and used by the cells of the body.

Teeth – Cut, Crush and tear food

Salivary glands – Moisten food to make it easier to chew and pass through the system, enzymes break down starches

Esophagus – Tube from mouth to stomach connected by Pharynx. Works by contraction of the smooth muscles known as peristalsis.

Stomach – Muscular sac that churns and mixes food with acid

Section 38-2

As food leaves the stomach it travels into the small intestine through the doudenum, and it mixes with with enzymes and digestive fluids from the liver, gallbladder and pancreas.

Liver

Gallbladder

Doudenum

Bile Duct

Pancreas

. Chemicals from the pancreas breakdown carbohydrates, proteins, lipids and nucleic acids. In addition chemicals from the pancreas produce substances which neutralize stomach acid.

If the acid travels too far without being neutralized it will change the shape of enzymes and cause problems in the body.

The Liver makes bile which acts like a detergent to break down fat. The gall bladder is a storage area for the bile

Small Intestine

Villus

Section 38-2

The small intestine absorbs nutrients from the digestive systems and transfers many of the nutrients to the circulatory system. The small intestine is lined with small fingerlike projections known as villi which designed to have a large surface area for this task.

Large intestine (Colon)

Food that enters the large intestine is nutrient-free. Usable nutrients have been absorbed leaving water and undigestible substances. The large intestine removes water from the waste. Once water is eliminated the solid waste passes out of the body through the rectum.

The appendix is located just below the entry to the large intestine. In many animals it

helps digest difficult materials such as cellulose. In humans the appendix is not used for any purpose

in digestion. When it gets infected it is removed.

D. Excretory System:

In the process of obtaining nutrients and carrying out chemical reactions the human body produces wastes (CO2, Urea, Salts). If some of these wastes are not removed they could threaten homeostasis. Excess chemicals that are not toxic also need to be removed.

The skin, lungs and kidneys all function to get rid of excess or harmful products

produced in the body.

Kidney Nephron

Section 38-3

Kidneys contain millions of small filters called nephrons, which filter your entire blood supply every 45 minutes. Filtration takes place because blood pressure forces water, salt, glucose, amino acids and urea into structures known as Bowman’s capsules. (Protein and Blood are too large to enter)

Bowman’s Capsule

Processes of osmosis and active transport filter the useful materials from the waste (urine). Substances your body needs to keep are returned to the blood stream. Substances your body needs to get rid of are passed from the renal tubes to the urinary bladder.

Kidney

Urinary Bladder

Ureter

Urethra

Vein Artery